1 B2 neutral
(Intransitive) Of a crowd, group, or density: to become smaller or less concentrated.
"After midnight, the crowd at the festival began to thin out."
inseparable
thin out
B2 neutral separable transitive/intransitive
To become less dense, crowded, or concentrated; or to make something less thick or dense.
In plain English
When things become fewer, or when you spread something out so there is less of it in one place.
What does "thin out" mean?
3 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B2 neutral
(Transitive) In gardening: to remove some plants or seedlings so that others have more space to grow.
"You should thin out the seedlings once they reach about five centimetres tall."
separable
3 B2 neutral
(Transitive) To dilute or reduce the thickness of a liquid or substance.
"Add a little water to thin out the paint before applying it."
separable
Literal vs figurative
Words literally mean
To become or make thinner outward.
Actually means
When things become fewer, or when you spread something out so there is less of it in one place.
Usage tip
Used both intransitively (the crowd thinned out) and transitively (thin out the seedlings / thin out a sauce). Common in gardening, cooking, and crowd/traffic contexts.
Words that pair with "thin out"
Natural word combinations native speakers use most often.
crowd traffic forest hair seedlings sauce
How to conjugate "thin out"
The five tense forms you'll use most often.
Base
thin out
I/you/we/they
3rd person
thins out
he/she/it
Past simple
thined out
yesterday
Past participle
thined out
have + pp
-ing form
thining out
continuous
Hear "thin out" in the wild
Listen to native speakers using "thin out" in real YouTube videos — click a clip to watch it on Looplines.
Keep exploring
Jump to every phrasal verb built on the same verb, particle, or level.